hash v2 and v3 help

[Normalitie]

Hi there - first post from a Python noob.

I'm trying to understand why some code in Python 2.7 works, yet when I try to port it across to Python 3.5 does not.

In Python 2.7

import hashlib
key = 'c41d9eac'
print(hmac.new(key, 'this is the life', hashlib.sha1).hexdigest())

>>> 537e629995a1ddd6c701c8b3563d06971a5cf751

In Python 3.5

import hashlib
key = 'c41d9eac'
print(hmac.new(b'key', b'this is the life', hashlib.sha1).hexdigest())

>>> e4b48f8bc8aa40fbc59fd88deb76bf4fc5e9b645

Any help would be much appreciated. I am really stumped on this.

R.